Hatching eggs - may be a few days different in age??

We just got our first incubator, a Genissis 1588. Started it up this weekend and ran over to my daughters friend to grab some practice eggs. She had a freshly laid one and then a hen was sitting on 3...which sage said may be a few days old. Put them all in the incubator. So how would I do lockdown when I may have 0-4 day old (already warned under a hen) eggs???